Traditionally, most commercially available inkjet printers have a print engine which forms part of the overall structure and design of the printer. In this regard, the body of the printer unit is typically constructed to accommodate the printhead and associated media delivery mechanisms, and these features are integral with the printer unit.
This is especially the case with inkjet printers that employ a printhead that traverses back and forth across the media as the media is progressed through the printer unit in small iterations. In such cases the reciprocating printhead is typically mounted to the body of the printer unit such that it can traverse the width of the printer unit between a media input roller and a media output roller, with the media input and output rollers forming part of the structure of the printer unit. With such a printer unit it may be possible to remove the printhead for replacement, however the other parts of the print engine, such as the media transport rollers, control circuitry and maintenance stations, are typically fixed within the printer unit and replacement of these parts is not possible without replacement of the entire printer unit.
As well as being rather fixed in their design construction, printer units employing reciprocating type printheads are considerably slow, particularly when performing print jobs of full colour and/or photo quality. This is due to the fact that the printhead must continually traverse the stationary media to deposit the ink on the surface of the media and it may take a number of swathes of the printhead to deposit one line of the image.
Recently, it has been possible to provide a printhead that extends the entire width of the print media so that the printhead can remain stationary as the media is transported past the printhead. Such systems greatly increase the speed at which printing can occur as the printhead no longer needs to perform a number of swathes to deposit a line of an image, but rather the printhead can deposit the ink on the media as it moves past at high speeds. Such printheads have made it possible to perform full colour 1600 dpi printing at speeds in the vicinity of 60 pages per minute, speeds previously unattainable with conventional inkjet printers.
Such a pagewidth printhead typically requires high precision and high speed paper movement, and as such, the entire print engine (printhead, paper handling mechanisms and control circuitry etc) must be configured accordingly to ensure high quality output.
Accordingly, there is a need to provide a print engine having a pagewidth printhead that can be readily employed within a standard body of a printer unit and is constructed in a manner that ensures that all the necessary parts of the print engine are configured in a manner that enables consistent high speed printing.
According to one aspect, the present invention provides a cartridge unit for an inkjet printer, the cartridge unit comprising:                an ink storage compartment and an ink feed system for connection to a printhead assembly with an array of ink ejection nozzles; wherein,        the ink storage compartment has a variable storage volume and a displaceable wall section biased to expand the variable storage volume to generate a negative pressure therein; such that,        ink does not inadvertently leak from the ink ejection nozzles.        
Without negative pressure, an ink meniscus can bulge from the nozzles. The meniscus will ‘pin’ itself to the edge of the nozzle aperture and may be strong enough to stop ink leakage. However, paper dust or other contaminants will eventually stop the bulging meniscus from pinning itself on the nozzle rim and leakage occurs. A negative pressure in the ink storage volume makes the meniscus invert back into the nozzle aperture. As the meniscus does not bulge out of the nozzle, paper dust on the nozzle surface does not break the surface tension to cause leakage.
In some embodiments, the ink storage compartment has opposed wall sections connected by a flexible wall arrangement to define the variable ink storage volume; such that one of the opposed wall sections is displaceable and biased to expand the variable ink storage volume. The opposed wall section may be biased with a constant force spring.
Optionally, the printhead assembly is fixed to the cartridge unit for removal and replacement therewith. In another option, the printhead assembly is a pagewidth printhead assembly.
In a first aspect the present invention provides a cartridge unit for an inkjet printer, the cartridge unit comprising:                an ink storage compartment and an ink feed system far connection to a printhead assembly with an array of ink ejection nozzles; wherein,        the ink storage compartment has a variable storage volume and a displaceable wall section biased to expand the variable storage volume to generate a negative pressure therein.        
Optionally the ink storage compartment has opposed wall sections connected by a flexible wall arrangement to define the variable ink storage volume; such that one of the opposed wall sections is displaceable and biased to expand the variable ink storage volume.
Optionally the opposed wall section is biased with a constant force spring.
Optionally the printhead assembly is fixed to the cartridge unit for removal and replacement therewith.
Optionally the printhead assembly is a pagewidth printhead assembly.
In a further aspect there is provided a cartridge unit, wherein:                the negatively pressurized ink storage compartment has an interface for receiving a refill unit for refilling the ink storage compartment, the interface having an inlet valve biased to its closed configuration; and        the refill unit comprises:                    a body containing a quantity of ink;            engagement formations for releasably engaging the interface; and            an inlet valve actuator for opening the inlet valve as the refill unit engages the ink interface so that the ink in the body is in fluid communication with the ink storage compartment.                        
In a further aspect there is provided a cartridge unit, wherein:                the negatively pressurized ink storage compartment has an interface for receiving an ink refill unit for refilling the ink storage compartment, the interface having a normally closed inlet valve and a normally open outlet valve, both in fluid communication with the ink storage compartment; and        the refill unit comprises:                    a body containing a quantity of ink; and            a docking portion having an ink outlet and valve actuator formations, the docking portion, during use, releasably engaging the interface to actuate the inlet and the outlet valves so the cartridge fills with ink from the body because of the negative pressure in the ink storage compartment.                        
In a further aspect there is provided a cartridge unit, wherein:                the negatively pressurized ink storage compartment is arranged to be refilled by a refill unit via a normally open outlet valve; and        the refill unit comprises:                    a body containing a quantity of ink;            engagement formations for releasably engaging the ink storage compartment; and            an outlet valve actuator for closing the outlet valve as the refill unit engages the ink storage compartment.                        
In a further aspect there is provided a cartridge unit, wherein:                the ink storage compartment is arranged to be refilled by a refill unit; and        the refill unit comprises:                    a body containing a quantity of ink;            an ink outlet; and            a repressurizing arrangement which, upon engagement of the refill unit with the ink storage compartment, causes part of the unit to be inwardly depressed as the ink from the body is drawn into the ink storage compartment through the ink outlet by the negative pressure until pressure equalization, and which, upon subsequent disengagement of the refill unit from the ink storage compartment, releases the inwardly depressed part of the ink storage compartment to re-establish the negative pressure.                        
In a further aspect there is provided a cartridge unit, wherein:                the ink storage compartment has opposed wall sections connected by a flexible wall arrangement to define the variable storage volume;        the cartridge unit further comprises an ink feed system for supplying for supplying ink to a printhead with an array of nozzles; and        one of the opposed wall sections is displaceable and biased to expand the variable storage volume to create a negative pressure in the ink storage compartment for avoiding inadvertent ink leakage from the nozzles.        
In a further aspect there is provided a cartridge unit, wherein:                the ink storage compartment has an interface for releasably engaging with a refill unit for refilling the ink storage compartment the interface having valves for controlling ink flows into, and out of, the storage compartment; and        the refill unit comprises:                    a body containing a quantity of ink;            an ink outlet; and,            valve actuators for actuating the valves when the refill unit engages the interface, such that the valve actuators actuate the valve in a predetermined sequence.                        
In a further aspect there is provided a cartridge unit, further comprising an interface for releasably engaging a refill unit for refilling the cartridge unit,                wherein the inkjet printer incorporates a printhead, control circuitry and the refill unit, the refill unit comprising:                    a body containing a quantity of ink;            an ink outlet; and            a memory circuit for storing information relating to at least one characteristic of the ink, which during use, allows the control circuit to interrogate it to verify that the ink in the refill unit is suitable for the printer.                        
In a further aspect there is provided a cartridge unit incorporating a printhead maintenance assembly for an inkjet printhead of the inkjet printer, the printhead having a nozzle plate with an array of nozzles formed therein,                wherein the printhead maintenance assembly comprises:                    a capper to cover the array of nozzles when the printhead is not in use; and            a cleaner for engaging the nozzle plate and wiping across the nozzles, the cleaner being positioned between opposing sides of the capper.                        
In a further aspect there is provided a cartridge unit, wherein the inkjet printer comprises:                a printhead with an array of nozzles;        a maintenance assembly for moving between a capped position where the assembly covers the array of nozzles, and an uncapped position spaced from the array of nozzles; and        a motorized drive for moving the maintenance assembly between the capped position and the uncapped position.        
In a further aspect there is provided a cartridge unit, further comprising an interface for engaging an ink refill unit for replenishing the cartridge, the ink refill unit comprising:                an ink storage compartment;        a docking portion for engaging the interface of the cartridge, the docking portion having a base plate with an ink outlet for connection to an inlet port on the interface; and        engagement formations for releasably engaging the interface, the engagement formations being formed on the transverse centre line of the base plate, the centre of the ink outlet being spaced from the transverse centre line.        
In a further aspect there is provided a cartridge unit, further comprising an interface for engaging an ink refill unit for replenishing the cartridge,                wherein the ink storage compartment is partially defined by a tubular flexible wall;        the cartridge unit further comprising a constriction mechanism for constricting the flexible tubular wall by a predetermined amount; and        the ink refill unit comprises:                    a body containing a quantity of ink; and            a docking portion for engaging the interface of the cartridge, the docking portion having an ink outlet for connection to as inlet port on the interface, and a plurality of constriction actuators for actuating the constriction mechanism as the ink refill unit engages the interface and releases the constriction mechanism as the ink refill unit disengages the interface.                        
In a further aspect there is provided a cartridge unit further comprising a refill unit and an interface for engaging an ink refill unit for replenishing the cartridge, the ink refill unit comprising:                a body containing a quantity of ink;        an ink outlet for engaging a complementary ink inlet in the interface; and        a spigot extending from the body for insertion in an aperture in the interface,        wherein the lateral cross section of the spigot is keyed to the shape defined by the aperture to ensure the ink refill is correctly matched to the cartridge.        
In a further aspect there is provided a cartridge unit engageable with an ink refill unit for replenishing the cartridge, the ink refill unit comprising:                a body containing ink;        an ink outlet for engaging a complementary ink inlet in the cartridge; and        a visual indicator to provide a visual indication when a predetermined quantity ink has flowed from the refill unit into the cartridge.        
In a further aspect there is provided a cartridge unit,                wherein the inkjet printer comprises:                    an outer casing with a hingedly mounted panel for access its interior;            a cradle housed within the outer casing for supporting an ink cartridge, the cradle having a hingedly mounted lid that opens to allow the ink cartridge to be inserted and removed,                        wherein the hinge axis of the lid and the hinge axis of the panel are parallel, and        wherein the lid and the panel both open in the same direction.        
In a further aspect there is provided a cartridge unit, wherein the inkjet printer comprises:                a replaceable pagewidth printhead with an array of nozzles and printhead contacts for transmitting power and print data to the nozzles;        corresponding contacts for supplying the power and print data to the printhead contacts; and        a selective biasing mechanism, such that the printhead contacts and the corresponding contacts are biased into engagement during printing and released from biased engagement when installing or removing the printhead.        
In a further aspect there is provided a cartridge unit, wherein the inkjet printer comprises:                a replaceable pagewidth printhead with an array of nozzles and printhead contacts for transmitting power and print data to the nozzles;        corresponding contacts for supplying the power and print data to the printhead contacts; and        a cover member for movement between open and closed positions, wherein, in the open positions, the printhead can be installed or removed, and the cover member is in the closed positions during printing, such that, the printhead contacts and the corresponding contacts are moved into engagement when the cover member is moved to the closed positions, and the printhead contacts and the corresponding contacts disengage when the cover member is moved to the open positions.        
In a further aspect there is provided a cartridge unit, further comprising:                an ink feed system for supplying ink from the or each ink compartment to a printhead; and        a maintenance station for engaging the printhead to perform one or more maintenance functions.        
In a further aspect there is provided a cartridge unit arranged to be held by a cradle within the inkjet printer, the cradle comprising a plurality of interfaces respectively corresponding to the storage compartments, each of the interfaces being configured to receive an ink refill unit for replenishing the corresponding ink storage compartment.
In a further aspect there is provided a cartridge unit, wherein the printer incorporates a printhead comprising:                a printhead integrated circuit formed on a wafer substrate using lithographically masked etching and deposition techniques;        an integrated circuit support structure for mounting in the printer adjacent a media feed path; and        a polymer sealing film between the integrated circuit support structure and the printhead integrated circuit for fixing the printhead integrated circuit to the integrated circuit support structure.        
In a further aspect there is provided a cartridge unit, wherein the printer incorporates a printhead comprising:                a printhead integrated circuit having an array of ink ejection nozzles formed on a substrate;        a plurality of ink feed conduits for establishing fluid communication with at least one ink storage compartment; and        a polymer sealing film between the ink feed conduits and the printhead integrated circuits, the polymer film having an array of apertures such that the ejection nozzles are in fluid communication with the ink feed conduits, polymer sealing film being more than 25 microns thick.        
In another aspect the present invention provides a cartridge unit for an inkjet printer, the cartridge unit comprising:                an ink storage compartment and an ink feed system for connection to a printhead assembly with an array of ink ejection nozzles; wherein,        the ink storage compartment has a variable storage volume and a displaceable wall section biased to expand the variable storage volume to generate a negative pressure therein; such that,        ink does not inadvertently leak from the ink ejection nozzles.        
In another aspect the present invention provides a refill unit for refilling a negatively pressurized ink storage compartment that supplies ink to a printhead assembly, the ink storage compartment having an interface for receiving the refill unit, the interface having an inlet valve biased to its closed configuration, the refill unit comprising:                a body containing a quantity of ink;        engagement formations for releasably engaging the interface; and        an inlet valve actuator for opening the inlet valve as the refill unit engages the ink interface so that the ink in the body is in fluid communication with the ink storage compartment.        
In another aspect the present invention provides an ink refill unit for an ink cartridge, the ink cartridge having a negatively pressurized ink storage compartment that supplies ink to a printhead assembly, and an interface for receiving the refill unit, the interface having a normally closed inlet valve and a normally open outlet valve, both in fluid communication with the ink storage compartment, the refill unit comprising:                a body containing a quantity of ink;        a docking portion having an ink outlet and valve actuator formations; wherein during use, the docking portion releasably engages the interface to actuate the inlet and the outlet valves so the cartridge fills with ink from the body because of the negative pressure in the ink storage compartment.        
In another aspect the present invention provides a refill unit for refilling a negatively pressurized ink storage compartment that supplies ink to a printhead assembly via a normally open outlet valve, the refill unit comprising:                a body containing a quantity of ink;        engagement formations for releasably engaging the ink storage compartment; and        an outlet valve actuator for closing the outlet valve as the refill unit engages the ink storage compartment.        
In another aspect the present invention provides a refill unit for refilling an ink storage compartment supplying a printhead assembly with an array of nozzles, wherein during use, the ink storage compartment is maintained at a negative pressure to avoid inadvertent ink leakage from the nozzles, the refill unit comprising:                a body containing a quantity of ink;        an ink outlet; and        a repressurizing arrangement; wherein,        upon engagement of the refill unit with the ink storage compartment, the repressurizing arrangement causes part of the cartridge to be inwardly depressed as the ink from the body is drawn into the ink storage compartment through the ink outlet by the negative pressure until pressure equalization; and,        upon subsequent disengagement of the refill unit from the ink storage compartment, the repressurizing arrangement releases the inwardly depressed part of the ink storage compartment to re-establish the negative pressure.        
In another aspect the present invention provides an ink cartridge for an inkjet printer, the cartridge comprising:                an ink storage compartment having opposed wall sections connected by a flexible wall arrangement to define a variable ink storage volume; and,        an ink feed system for supplying for supplying ink to a printhead with an array of nozzles; wherein,        one of the opposed wall sections is displaceable and biased to expand the variable ink storage volume to create a negative pressure in the ink storage compartment for avoiding inadvertent ink leakage from the nozzles.        
In another aspect the present invention provides a refill unit for refilling an ink storage compartment with an interface for releasably engaging with the refill unit, the interface having valves for controlling ink flows into, and out of, the storage compartment, the refill unit comprising:                a body containing a quantity of ink;        an ink outlet; and,        valve actuators for actuating the valves when the refill unit engages the interface; such that,        the valve actuators actuate the valve in a predetermined sequence.        
In another aspect the present invention provides a refill unit for refilling an ink cartridge that forms part of an inkjet printer, the printer also having a printhead, control circuitry and an interface for releasably engaging the refill unit, the refill unit comprising:                a body containing a quantity of ink;        an ink outlet; and        a memory circuit for storing information relating to at least one characteristic of the ink; wherein during use,        the memory circuit allows to the control circuit to interrogate it to verify that the ink in the refill unit is suitable for the printer.        
In another aspect the present invention provides a printhead maintenance assembly for an inkjet printhead, the printhead having a nozzle plate with an array of nozzles formed therein, the printhead maintenance assembly comprising:                a capper to cover the array of nozzles when the printhead is not in use; and,        a cleaner for engaging the nozzle plate and wiping across the nozzles; wherein,        the cleaner is positioned between opposing sides of the capper.        
In another aspect the present invention provides an inkjet printer comprising:                a printhead with an array of nozzles;        a maintenance assembly for moving between a capped position where the assembly covers the array of nozzles, and an uncapped position spaced from the array of nozzles; and,        a motorized drive for moving the maintenance assembly between the capped position and the uncapped position.        
In another aspect the present invention provides an ink refill unit for replenishing an ink cartridge in an inkjet printer, the ink cartridge having an interface for engaging the ink refill unit, the ink refill unit comprising:                an ink storage compartment;        a docking portion for engaging the interface of the cartridge, the docking portion having a base plate with an ink outlet for connection to an inlet port on the interface;        engagement formations for releasably engaging the interface, the engagement formations being formed on the transverse centre line of the base plate; wherein,        the centre of the ink outlet is spaced from the transverse centre line.        
In another aspect the present invention provides an ink refill and for replenishing an ink cartridge in an inkjet printer, the ink cartridge having an interface for engaging the ink refill an ink storage compartment partially defined by a tubular flexible wall, and a constriction mechanism for constricting the flexible tubular wall by a predetermined amount, the ink refill unit comprising:                a body containing a quantity of ink;        a docking portion for engaging the interface of the cartridge, the docking portion having an ink outlet for connection to an inlet port on the interface, and a plurality of constriction actuators for actuating the constriction mechanism as the ink refill unit engages the interface and releases the constriction mechanism as the ink refill unit disengages the interface.        
In another aspect the present invention provides an ink refill unit for replenishing an ink cartridge in an inkjet printer, the ink cartridge having an interface for engaging the ink refill unit, the ink refill unit comprising:                a body containing a quantity of ink;        an ink outlet for engaging a complementary ink inlet in the interface; and,        a spigot extending from the body for insertion in an aperture in the interface; wherein,        the lateral cross section of the spigot is keyed to the shape defined by the aperture to ensure the ink refill is correctly matched to the cartridge.        
In another aspect the present invention provides an ink refill unit for replenishing an ink cartridge in an inkjet printer, the ink refill unit comprising:                a body containing ink;        an ink outlet for engaging a complementary ink inlet in the cartridge; and,        a visual indicator to provide a visual indication when a predetermined quantity ink has flowed from the refill unit into the cartridge.        
In another aspect the present invention provides an inkjet printer comprising:                an outer casing with a hingedly mounted panel for access its interior;        a cradle housed within the outer casing for supporting an ink cartridge, the cradle having a hingedly mounted lid that opens to allow the ink cartridge to be inserted and removed; wherein,        the hinge axis of the lid and the hinge axis of the panel are parallel; and,        the lid and the panel both open in the same direction.        
In another aspect the present invention provides an inkjet printer comprising:                a replaceable pagewidth printhead with an array of nozzles and printhead contacts for transmitting power and print data to the nozzles; and,        corresponding contacts for supplying the power and print data to the printhead contacts; and,        a selective biasing mechanism; such that,        the printhead contacts and the corresponding contacts are biased into engagement during printing and released from biased engagement when installing or removing the printhead.        
In another aspect the present invention provides an inkjet printer comprising:                a replaceable pagewidth printhead with an array of nozzles and printhead contacts for transmitting power and print data to the nozzles; and,        corresponding contacts for supplying the power and print data to the printhead contacts; and,        a cover member for movement between open and closed positions; wherein,        in the open positions, the printhead can be installed or removed, and the cover member is in the closed positions during printing; such that,        the printhead contacts and the corresponding contacts are moved into engagement when the cover member is moved to the closed positions, and the printhead contacts and the corresponding contacts disengage when the cover member is moved to the open positions.        
In another aspect the present invention provides a cartridge for an inkjet printer, the cartridge comprising:                at least one ink storage compartment;        an ink feed system for supplying ink from the or each ink compartment to a printhead; and,        a maintenance station for engaging the printhead to perform one or more maintenance functions.        
In another aspect the present invention provides a cradle for holding an ink cartridge within an inkjet printer, the cartridge having a plurality of ink storage compartments, the cradle comprising:                a plurality of interfaces respectively corresponding to the ink storage compartments; wherein,        each of the interfaces is configured to receive an ink refill unit for replenishing the corresponding ink storage compartment.        
In another aspect the present invention provides a printhead comprising:                A printhead integrated circuit formed on a wafer substrate using lithographically masked etching and deposition techniques;        An integrated circuit support structure for mounting in the printer adjacent a media feed path; and,        A polymer sealing film between the integrated circuit support structure and the printhead integrated circuit for fixing the printhead integrated circuit to the integrated circuit support structure.        
In another aspect the present invention provides a printhead for an inkjet printer, the printhead comprising:                a printhead integrated circuit having an array of ink ejection nozzles formed on a substrate;        a plurality of ink feed conduits for establishing fluid communication with at least one ink storage compartment; and,        a polymer sealing film between the ink feed conduits and the printhead integrated circuits, the polymer film having an array of apertures such that the ejection nozzles are in fluid communication with the ink feed conduits; wherein,        the polymer sealing film is more than 25 microns thick.        
In another aspect, the present invention provides a printhead integrated circuit comprising:                a plurality nozzles formed on a frontside of a substrate, each nozzle having a respective nozzle inlet; and        a plurality of ink supply channels, each ink supply channel being configured for supplying ink from a backside of the substrate to a corresponding group of nozzle inlets,        wherein each ink supply channel is dimensioned for receiving ink from one or more outlets in a molded ink manifold.        
In another aspect, the present invention provides a printhead integrated circuit comprising:                a plurality nozzles formed on a frontside of a substrate, the nozzles being arranged in rows extending longitudinally along the substrate, each nozzle having a respective nozzle inlet; and        a plurality of ink supply channels extending longitudinally along a backside of the substrate, each ink supply channel being configured for supplying ink from the backside to at least one corresponding row of nozzle inlets,        wherein each ink supply channel is interrupted along its length by one or more transverse bridges.        
In another aspect, the present invention provides a printhead integrated circuit comprising:                a plurality of nozzles formed on a frontside of a substrate, each nozzle having a respective nozzle inlet; and        a plurality of ink supply channels, each ink supply channel being configured for supplying ink from a backside of the substrate to a corresponding group of nozzle inlets,        wherein each ink supply channel has an aspect ratio of less than 4:1, the aspect ratio being defined by the ratio of the channel depth to the channel width.        
Optionally the nozzles are arranged in rows, each row extending longitudinally along the frontside, each ink supply channel extending longitudinally along the backside and being configured for supplying ink from the backside to at least one corresponding row of nozzle inlets.
Optionally the nozzles are arranged in pairs of rows, each paired row extending longitudinally along the frontside, each ink supply channel extending longitudinally along the backside and being configured for supplying ink from the backside to a corresponding paired row of nozzle inlets.
Optionally each ink supply channel has a width dimension of at least 50 microns.
Optionally each ink supply channel has a width dimension of at least 70 microns.
Optionally each ink supply channel is interrupted along its length by one or more transverse bridges.
Optionally channel sections are defined by a plurality of transverse bridges spaced apart along each ink supply channel.
Optionally each transverse bridge is configured such that each channel section is sealed from its adjacent channel section.
Optionally each transverse bridge is configured such that ink flows longitudinally between adjacent channel sections.
Optionally each ink supply channel has an aspect ratio of less than 4:1, the aspect ratio being defined by the ratio of the channel depth to the channel width.
Optionally each ink supply channel has an aspect ratio of less than 2:1.
Optionally the substrate has a thickness in the range of 100 to 500 microns.
Optionally the pagewidth inkjet printhead comprising a plurality of printhead integrated circuits.
In a further aspect there is provided a pagewidth inkjet printhead comprising:                a plurality of nozzles formed on a frontside of a substrate, each nozzle having a respective nozzle inlet; and        a plurality of ink supply channels, each ink supply channel being configured for supplying ink from a backside of the substrate to a corresponding group of nozzle inlets,        wherein each ink supply channel is dimensioned for receiving ink from one or more outlets in a moulded ink manifold.        
In another aspect there is provided a pagewidth inkjet printhead assembly comprising:                the printhead; and        a moulded ink manifold bonded to the backside of the printhead, the ink manifold having a plurality of outlets, each outlet being aligned with an ink supply channel.        
Optionally the printhead is bonded to the ink manifold by an adhesive film sandwiched between the printhead and the ink manifold.
Optionally a plurality of openings are defined in the adhesive film, each opening being positioned for allowing ink to flow from one of said outlets to an ink supply channel.
Optionally each outlet and each opening is positioned over a transverse bridge, such that ink is supplied from the ink manifold to two channel sections on either side of the transverse bridge.
Optionally a printer comprising the printhead assembly.
Optionally channel sections are defined by a plurality of transverse bridges spaced apart along each ink supply channel.
Optionally the longitudinal distance between each transverse bridge is at least 1000 microns.
Optionally each transverse bridge is configured such that each channel section is sealed from its adjacent channel section.
Optionally each transverse bridge is configured such that ink flows longitudinally between adjacent channel sections.
Optionally the nozzles are arranged in pairs of rows, each paired row extending longitudinally along the frontside, each ink supply channel extending longitudinally along the backside and being configured for supplying ink from the backside to a corresponding paired row of nozzle inlets.
Optionally each ink supply channel has a width dimension of at least 50 microns.
Optionally each ink supply channel has a width dimension of at least 70 microns.
Optionally each ink supply channel has an aspect ratio of less than 4:1, the aspect ratio being defined by the ratio of the channel depth to the channel width.
Optionally each ink supply channel has an aspect ratio of less than 2:1.
Optionally the substrate has a thickness in the range of 100 to 500 microns.
Optionally the substrate has a thickness in the range of 120 to 250 microns.
Optionally a pagewidth inkjet printhead comprising a plurality of printhead integrated circuits.
In a further aspect there is provided a pagewidth inkjet printhead comprising:                a plurality of nozzles formed on a frontside of a substrate, the nozzles being arranged to rows extending longitudinally along the substrate, each nozzle having a respective nozzle inlet; and        a plurality of ink supply channels extending longitudinally along a backside of the substrate, each ink supply channel being configured for supplying ink from the backside to a corresponding row of nozzle inlets,        wherein each ink supply channel is interrupted along its length by one or more transverse bridges.        
In another aspect there is provided pagewidth inkjet printhead assembly comprising:                the printhead; and        a moulded ink manifold bonded to the backside of the printhead, the ink manifold having a plurality of outlets, each outlet being aligned with an ink supply channel.        
Optionally the printhead is bonded to the ink manifold by an adhesive film sandwiched between the printhead and the ink manifold.
Optionally a plurality of openings are defined in the adhesive film, each opening being positioned for allowing ink to flow from one of said outlets to an ink supply channel.
Optionally each outlet and each opening is positioned over a transverse bridge, such that ink is supplied from the ink manifold to two channel sections on either side of the transverse bridge.
Optionally a printer comprising the printhead assembly.
Optionally a printer which is a pagewidth inkjet printer.
Optionally each ink supply channel has an aspect ratio of less than 3:1
Optionally each ink supply channel has an aspect ratio of less than 2:1.
Optionally each ink supply channel is dimensioned for receiving ink from one or more outlets in a moulded ink manifold.
Optionally the substrate has a thickness in the range of 100 to 500 microns.
Optionally the nozzles are arranged in rows, each row extending longitudinally along the frontside, each ink supply channel extending longitudinally along the backside and being configured for supplying ink from the backside to at least one corresponding row of nozzle inlets.
Optionally the nozzles are arranged in pairs of rows, each paired row extending longitudinally along the frontside, each ink supply channel extending longitudinally along the backside and being configured for supplying ink from the backside to a corresponding paired row of nozzle inlets.
Optionally each ink supply channel has a width dimension of at least 50 microns.
Optionally each ink supply channel has a width dimension of at least 70 microns.
Optionally each ink supply channel is interrupted along its length by one or more transverse bridges.
Optionally channel sections are defined by a plurality of transverse bridges spaced apart along each ink supply channel.
Optionally each transverse bridge is configured such that each channel section is sealed from its adjacent channel section.
Optionally each transverse bridge is configured such that ink flows longitudinally between adjacent channel sections.
Optionally pagewidth inkjet printhead comprising a plurality of printhead integrated circuits.
In a further aspect there is provided a pagewidth inkjet printhead comprising:                a plurality of nozzles formed on a frontside of a substrate, each nozzle having a respective nozzle inlet; and        a plurality of ink supply channels, each ink supply channel being configured for supplying ink from a backside of the substrate to a corresponding group of nozzle inlets,        wherein each ink supply channel has an aspect ratio of less than 4:1, the aspect ratio being defined by the ratio of the channel depth to the channel width.        
In another aspect there is provided a pagewidth inkjet printhead assembly comprising:                the printhead; and        a moulded ink manifold bonded to the backside of the printhead, the ink manifold having a plurality of outlets, each outlet being aligned with an ink supply channel.        
Optionally the printhead is bonded to the ink manifold by an adhesive film sandwiched between the printhead and the ink manifold.
Optionally a plurality of openings are defined in the adhesive film, each opening being positioned for allowing ink to flow from one of said outlets to an ink supply channel.
Optionally each outlet and each opening is positioned over a transverse bridge, such that ink is supplied from the ink manifold to two channel, sections on either side of the transverse bridge.
Optionally a printer comprising the printhead assembly.